True, the U.S. has had more heat waves in recent years—but no more than a century ago.

The world’s response to climate changing under natural and human influences is best founded upon a complete portrayal of the science. The U.S. government’s Climate Science Special Report, to be released Friday, does not provide that foundation. Instead, it reinforces alarm with incomplete information and highlights the need for more-rigorous review of climate assessments.

A team of some 30 authors chartered by the U.S. Global Change Research Program began work in spring 2016 on the report, “designed to be an authoritative assessment of the science of climate change.” An early draft was released for public comment in January and reviewed by the National Academies this spring. I, together with thousands of other scientists, had the opportunity to scrutinize and discuss the final draft when it was publicized in August by the New York Times . While much is right in the report, it is misleading in more than a few important places.

One notable example of alarm-raising is the description of sea-level rise, one of the greatest climate concerns. The report ominously notes that while global sea level rose an average 0.05 inch a year during most of the 20th century, it has risen at about twice that rate since 1993. But it fails to mention that the rate fluctuated by comparable amounts several times during the 20th century. The same research papers the report cites show that recent rates are statistically indistinguishable from peak rates earlier in the 20th century, when human influences on the climate were much smaller. The report thus misleads by omission.

This isn’t the only example of highlighting a recent trend but failing to place it in complete historical context. The report’s executive summary declares that U.S. heat waves have become more common since the mid-1960s, although acknowledging the 1930s Dust Bowl as the peak period for extreme heat. Yet buried deep in the report is a figure showing that heat waves are no more frequent today than in 1900. This artifice also appeared in the government’s 2014 National Climate Assessment, which emphasized a post-1980 increase in hurricane power without discussing the longer-term record. The National Oceanic and Atmospheric Administration recently stated that it has been unable to detect any human impact on hurricanes.

Such data misrepresentations violate basic scientific norms. In his celebrated 1974 “Cargo Cult” lecture, the late Richard Feynman admonished scientists to discuss objectively all the relevant evidence, even that which does not support the narrative. That’s the difference between science and advocacy.

These deficiencies in the new climate report are typical of many others that set the report’s tone. Consider the different perception that results from “sea level is rising no more rapidly than it did in 1940” instead of “sea level rise has accelerated in recent decades,” or from “heat waves are no more common now than they were in 1900” versus “heat waves have become more frequent since 1960.” Both statements in each pair are true, but each alone fails to tell the full story.

Several actions are warranted. First, the report should be amended to describe the history of sea-level rise, heat waves and other trends fully and accurately. Second, the government should convene a “Red/Blue” adversarial review to stress-test the entire report, as I urged in April. Critics argue such an exercise would be superfluous given the conventional review processes, and others have questioned even the minimal time and expense that would be involved. But the report’s deficiencies demonstrate why such a review is necessary.

Finally, the institutions involved in the report should figure out how and why such shortcomings survived multiple rounds of review. How, for example, did the National Academies’ review committee conclude that the chapter on sea level rise “accurately reflects the current scientific literature on this topic”? The Academies building prominently displays Einstein’s dictum “one must not conceal any part of what one has recognized to be true.”

Mr. Koonin was undersecretary of energy for science during President Obama’s first term and is director of the Center for Urban Science and Progress at New York University.